The present disclosure generally relates to systems and methods for preparing an oil or gas well. More specifically, the present disclosure relates to systems and methods for attaching and securing a wellhead to the surface casing for use in a drilling or work over operation.
A wellhead assembly includes several components of drilling machinery which must be sealingly attached to a terminal end of the surface casing extending into a drilled well. Due to the vertical height of the fully assembled wellhead, the surface casing is typically terminated at a distance several feet below the surface of the Earth within a constructed cellar. By creating a cellar and terminating the surface casing within the cellar, controls on the highest components of the wellhead assembly are accessible from the surface for operation of the well.
The wellhead attachment to the surface casing must be capable of withstanding pressures of at least 0 to 10,000 psi. Traditionally, this attachment has been achieved by welding the wellhead to a landing mandrel attached to the terminal end of the surface casing within the cellar. This welding task is complex due to the tight quarters of the cellar, the size of the wellhead assembly and the time required to sealingly weld the entire circumference of the landing mandrel. As a result, the current method of connecting the wellhead assembly to the landing mandrel consumes additional labor and resources, and necessitates the use of the drilling rig to support the wellhead assembly in place during welding, rather than freeing the drilling rig for other necessary drilling preparation tasks.
Therefore, a need exists for a cost- and time-effective way to properly and sealingly attach the wellhead assembly to the landing mandrel of the surface casing without monopolizing use of the drilling rig during the valuable well-preparation period.